There's a problem with AP Itemization

, , and

I kinda feel like it's holding you back from making AP Melee items.

Abyssal occupies the AP + MR +Magic pen space and yet makes it only good for melee in specific scenario.

Haunting Guise on the other hand takes the AP + Health + Magic Pen space and feels great for both classes and yet it ends up being Liandry's little pet - similar to Season 2 Yommuu's.

Seekers is more along the lines of lack of AP Armour items that isn't Zhonyas

So maybe consider splitting Abyssal into an MR AP item (say Wisp + MR = Force of Nature), and a magic pen item that builds off of Liandry's and is great for Melee tanky mages, whilst provinding a damage alternative to armour items for AP Tanks (maybe Haunting + Seekers lol) .